1. Field of the Invention
The invention generally relates to composite fabrics having unique aesthetic and physical features, and methods for their manufacture. More specifically, the invention relates to fabric constructions incorporating a layer of diffractive or retroreflective material behind a layer of textile material, to provide unique visual appearances in durable fabric constructions. Methods for making such fabric constructions and articles illustrating exemplary uses of the fabric constructions are also described.
2. Description of the Prior Art
Fabric manufacturers continually strive to develop new fabric constructions having unique visual characteristics, in order to satisfy consumer demand for variety in the appearance of the items they purchase. Furthermore, manufacturers are constantly attempting to provide fabrics with enhanced performance characteristics, as well as to minimize expenses associated with the use and conversion of the materials that they produce. With that in mind, many manufacturers have attempted to incorporate metallic elements, glitter, and other types of reflective materials into their fabrics in order to provide the materials with a shiny visual appearance, and reflective and/or retroreflective capabilities. In some cases, the incorporation of such elements is done for aesthetic reasons alone, while in others the elements are required to provide the fabrics with specific functional characteristics. For example, such materials are used in the production of items of reflective apparel for wear by nighttime joggers, in order that they will be more easily observed by the drivers of oncoming vehicles.
One method currently used for including colorful, shiny and/or reflective particulate to textile fabrics is to apply the particulate to the face of the fabric, generally by using a binder resin for adhesion. While fabrics made by this method are relatively simple to produce, they have several distinct disadvantages. For one, both the binder resin and the particulate adversely affect the hand of the fabric, rendering such fabrics unacceptable for some end uses. In addition, the particulate is susceptible to being abraded off, which reduces the effective life of the fabric and can be problematic, since the particulate matter is then undesirably transferred to other articles. Furthermore, the size of the particles which can be used to manufacture such fabrics is limited, as large particles are particularly prone to rubbing off and they adversely affect the hand to a greater degree then smaller particles. The applications for such materials can also be limited, particularly due to the difficulties with molding such materials. Not only does the binder have a tendency to melt during molding operations, but the particulate and binder tend to come off of the fabric during the molding process.
Another method for incorporating reflective materials into a fabric is to laminate a shiny material to the outer surface of a piece of fabric. For example, U.S. Pat. No. 5,593,765 to Sharpe describes a flexible laminate having an outer visible layer providing a holographic effect. The laminate includes a layer of metal foil bearing a holographic image, a layer of flexible fabric, and an adhesive layer between the fabric and the foil. The adhesive layer includes at least one plastics material, and the laminate is intended to behave essentially as the flexible fabric so that clothing can be manufactured from the fabric. However, because the holographic foil is unprotected in this construction, it can be easily damaged during use of the article which it is used to construct.
Another method for incorporating reflective elements into fabrics involves incorporating reflective yarns into the fabric structure itself. Some prior fabrics utilize reflective filaments which are woven or otherwise incorporated with other yarns to form a part of the fabric structure itself. For example, U.S. Pat. No. 5,224,439 to O""Connell describes a reflective arrow mount for securement to an automobile at a traffic or emergency scene. The fabric forming the arrow includes a plurality of light reflective filaments running along at least some of its edge portions, with the filaments being selected to present a highly illuminated configuration of the arrow when lit up by the headlights of an oncoming motor vehicle at night. It is noted, however, that the reflective filaments do not produce any measurable effect during daylight.
Similarly, U.S. Pat. No. 5,804,275 to Tsunefuji describes products made from flat threads in which triangular, pyramid-like or otherwise shaped micro-prisms are formed. The prisms are shaped such that incident light from a light source is reflected three times at the surfaces of each of the micro-prisms to direct the reflected light back in a direction opposite to the direction of incidence. While both the O""Connell and Tsunefuji patents describe materials which can reflect light at night, they are each designed to appear as a normal non-reflective fabric during the daylight. Furthermore, the appearance of the light reflected would be the same as the color of the light which it receives.
U.S. Pat. No. 4,187,332 to Fouche, Jr. describes a process for producing wash resistant light-reflective fabrics for use in garments and wearing apparel to enhance nighttime visibility without significantly detracting from their daytime visual appearance. The process involves applying to a surface of a textile fabric constructed from differentially dyed or dyeable yarns or fibers a liquid paste composition containing a uniform dispersion of binder-coated, reflex-reflective, magnetically orientable particles suspended therein. A magnetic force field is applied to the fabric during its production so that the particles are oriented in the paste composition with their light reflecting surfaces disposed outwardly. Like the O""Connell and Tsunefuji patents described above, fabrics made according to the Fouche, Jr. patent are designed to appear to be non-reflective in the daylight, and the reflected light has the same appearance as what is received.
U.S. Pat. No. 5,882,770 to Makansi describes fabrics having rainbow and hologram images. A fibrous sheet is provided with an outer surface having fibrous elements which are embossed with a pattern of fine grooves that are substantially aligned from fibrous element to fibrous element. The pattern of fine grooves is embossed directly on the surface of the fibrous sheet and produces rainbow and/or hologram images on exposure to light. The fabric is designed to be free from plastic or metal foils.
Heretofore, none of the prior art methods for providing such reflective or retroreflective fabrics has achieved a combination of good hand and durability while providing desirable levels of light reflection. Further, a need exists for a fabric having desirable reflective characteristics and which can be readily and efficiently molded into three-dimensional shapes.
The instant invention overcomes the deficiencies of the prior art by providing fabric constructions which have superior durability and which provide a unique and aesthetically pleasing appearance. In addition, the fabrics of the instant invention can be manufactured to provide retroreflection and diffraction capabilities that will render items made from or containing the fabrics extremely conspicuous to observers. The fabrics can thus be utilized to enhance the visibility of certain articles, such as for automobile safety equipment and the like. Furthermore, the fabrics of the instant invention can be readily and efficiently manufactured, and can be used in the construction of a wide variety of end products.
The invention achieves these advantages by way of a composite fabric having a layer of textile fabric which forms the visual surface of the fabric, and a layer of diffractive or retroreflective material positioned and secured beneath the textile fabric layer. For purposes of this patent disclosure, the terms xe2x80x9couterxe2x80x9d and xe2x80x9cvisualxe2x80x9d surface of the fabric are intended to describe the side of the fabric which is designed to be the aesthetic or xe2x80x9crightxe2x80x9d side of the fabric. In other words, when the fabric is used to form an article, this side will be positioned to be the surface readily viewed by a user. For example, it would form the outer surface of an item of apparel, the surface of a door panel which is viewed by an observer, etc.
For purposes of the invention, the term xe2x80x9cdiffractivexe2x80x9d describes materials that cause a diffraction, i.e. a redistribution in space of the intensity of waves that results from the presence of an object causing variations of either the amplitude or phase of the waves. In a preferred form of the invention, this is accomplished using a holographically embossed diffraction film or another form of diffraction grating (i.e. an optical device consisting of an assembly of narrow slits or grooves which produce a large number of beams that can interfere to produce interference spectra or patterns.) The term xe2x80x9cretroreflectivexe2x80x9d describes materials that reflect light under retroreflective lighting conditions (i.e. ambient light that is substantially collimated, such as the light cast by the headlight of an automobile, a flashlight or the like) and reflect the light so that the paths of the rays are parallel to those of the incident rays. As a result, the light rays are reflected directly back toward their source. Retroreflective materials generally utilize transparent microspheres, typically with hemispheric retroreflectors thereon, or prismatic designs incorporating one or more structures commonly known as cube corners. Examples of retroreflective materials which can be used in the instant invention are described in U.S. Pat. No. 5,962,121 to Mori and U.S. Pat. No. 5,962,108 to Nestegard et al., although other types of retroreflective materials may also be used within the scope of the instant invention.
The textile fabric is selected to enable at least a portion of the layer of diffractive or retroreflective material to be seen through the fabric. In one embodiment of the invention, this is achieved through the utilization of a mesh-like layer of textile fabric which has a plurality of openings between the fabric-forming yarns which enable viewing of the diffractive or retroreflective material layer. In another embodiment of the invention, the textile fabric is semi-transparent, such that the layer of diffractive or retroreflective material can reflect light through the layer of textile fabric.
In other aspects of the invention, additional layers of material are included to provide additional structural rigidity to the composite material. For example, an intermediate layer such as a generally clear or transparent film layer or the like can be provided between the layer of textile fabric and the layer of diffractive or retroreflective material, so long as the intermediate layer does not obscure or undesirably impinge on the ability of the diffractive or retroreflective material to receive and reflect light through the textile fabric layer. In addition to or alternatively, an additional layer of material can be provided beneath the layer of diffractive or retroreflective material. For example, a layer of foam, a woven, knit or nonwoven layer of material, or the like can be used within the scope of the invention. The material can be selected to provide the amount of structural rigidity desired for the composite fabric. As will be readily appreciated by those of ordinary skill in the art, a plurality of additional layers can be included within the scope of the invention, in order to contribute to the attainment of the desired features. In addition, the material can be selected to be easily moldable, such that the composite fabric can be used to form three-dimensional molded articles.
The layer of diffractive or retroreflective material can assume a variety of forms according to the instant invention. In one embodiment, the layer of diffractive or retroreflective material is provided as a substantially continuous film layer, which is laminated, adhesively secured, or otherwise attached beneath the rear surface of the textile fabric layer. As noted above, the layer of diffractive or retroreflective material can be secured directly to the rear surface of the layer of textile fabric or it can be secured to a generally transparent intermediate layer which is in turn secured to the rear surface of the textile fabric layer. The layer of diffractive or retroreflective material can also be provided in the form of a plurality of strands (e.g. as filaments or yarns formed partially or entirely from a diffractive or retroreflective material.) Such strands can be manufactured, for example, by slitting a sheet of diffractive or retroreflective material into a plurality of relatively narrow strips. These strands can be secured directly to the rear surface of the layer of textile fabric or sandwiched between the layer of textile fabric and another material such as a layer of foam, a layer of woven, knit or nonwoven material, or the like.
As a further alternative, the diffractive or retroreflective layer can comprise a plurality of particles. The particles can be sandwiched between the textile fabric layer and an additional layer of material, beneath a generally transparent layer which is secured to the textile fabric layer, within a generally transparent layer secured to the rear surface of the textile fabric layer, or the like. In one embodiment of the invention, the textile fabric layer has a plurality of openings and the particles have a dimension which is smaller than that of the openings. In some versions of this embodiment of the invention, only a portion of a diffractive or retroreflective particle appears in an opening in the textile fabric layer while in others, a number of particles can fit in each of the openings in the textile fabric layer. In other embodiments, the particles can be larger than individual openings in the textile fabric layer. The particles can be spread apart or overlapping, depending on the visual appearance and physical properties which are desired to be achieved.
The diffractive or retroreflective material can be colored, designed, patterned, or otherwise ornamented as desired. In addition, the diffractive or retroreflective material can be provided in a pattern with respect to the textile material. For example, the diffractive or retroreflective material could be printed or otherwise secured to a substrate so that it forms a pattern (e.g. a corporate logo, a symbol advising that assistance is needed, etc.) Furthermore, in embodiments of the invention using a holographically-embossed diffraction film to form the diffractive or retroreflective layer, the film can be embossed in any manner (e.g. with geometric shapes, logos, or the like.)
The fabrics made according to the invention thus possess a unique aesthetic appearance. In addition, in the embodiments where a diffractive layer is utilized, a particularly conspicuous fabric can be obtained, due to the color spectrum produced as the light is diffracted and the way the spectrum changes as the observer moves relative to the fabric. As a result, such fabrics have particular utility in the formation of articles designed to alert an observer of the presence of an object (e.g. a trunk liner designed to alert oncoming traffic to the presence of a stalled vehicle and the like.)